It wasn’t fighting Russian-speaking separatists in Ukraine that spurred Roman Nabozhniak to stop speaking Russian. It was being misidentified on vacation as a Russian.
Ukrainian vs. Russian Language
Christian Science Monitor: Why Russian vs. Ukrainian divides so deeply
A woman holds a poster reading "Don't like language (Ukrainian)? Then go to Rostov!'" as she attends a rally in support of the Ukrainian language in front of the parliament building on July 16, 2020.